<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script src="./js/vue.js"></script>
    <div class="box">
        <p>v-on</p>
        <h1>{{counter}}</h1>
        <button @click="increment">+</button>
        <button @click="decrement">-</button>
    </div>
    <script>
        const vm_On = new Vue({
            el: '.box',
            data: {
                counter: 0
            },
            methods: {
                increment() {
                    this.counter++
                },
                decrement() {
                    this.counter--
                }
            }

        })
    </script>
</body>

</html>